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Discussion Starter #1
Hey experts, First post.

I just bought my daughter a 2000 ML 320 with 68K miles. It seems like a winner so far. I have been doing the 60K service myself for the most part. I took it to my excellent indie MB mechanic for the plugs, bleed and replace the brake fluid, etc.

He just called and said the plugs were too tight to safely remove. He was worried that if something broke he would have the remove a good head to fix it. He said they were probably good till 100K and since the engine was running well and had not stored any misfire codes, he said to just leave them for now. Wow, I have always been able to get plugs out myself, but this guy is good and I trust him.

Anybody else seen this trouble? Any tricks to get them out without breaking a plug off in the head or stripping the head?

BTW, the first time I filled up with gas, the fuel gauge messed up and read out of gas. After a day of driving, it started to work again. I have read the posts about the fuel sending/pump failures. Misery loves company! :)

Thanks,

Ken

91 560 SEL for sale :crybaby2: daughter does not want to drive it! :confused:
2000 ml320
2007 ml350
2007 e350 se
 

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When I first changed the plugs on my ML430 at circa 70,000 miles I also found them to be very tight. This was after leaving the engine to cool down for 24 hours - but after resorting to a breaker bar of a few of them they came out ok.

Maybe your mechanic is being overly cautious for your sake !

Rightly or wrongly when I installed the new plugs a used a small dab of anti-seaze compound - so far more than 20,000 miles later all is good.

Welcome to the forum I'm sure you'll find it a treasure trove of useful info - plus a few 'characters' :)
 

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Discussion Starter #3
Thanks Tim,

I wondered the same thing. But I have not messed with many aluminum heads. I just always would move up to my 1/2 rachet and power them off. But I would be pissed if I had to pull a good head...

I am a beliver in anti- seize. It works. I searched around on the net and saw suggestions like freezing the plug with cold spray, torching the head ( bad idea) and liberal amonts of penetrating oil. I guess I will just wait until it starts to misfire. But with gas prices they way they are, I am sure it would help to get those plugs out. I wonder what the dealer would do if they broke the threads...
 

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1999 ML430, 2007 R320 CDI, 2002 Yamaha YZF600R, 2007 Kawazaki ZX14
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Spark plugs

I also think that the mechanic is being very cautious. I changed the plugs on my 99 ML430 last week end. Some plugs were very tight. The truck has 101K miles on the first set of plugs. But all in all it was not bad. I broke 1 plug whiletaking the metal boot off. It was stuck in the boot and using the spark plug socket, I was able to get the rest if it out. Thankfully the other half with the electrodes did not fell into the cylinder. The biggest difference is the milage. It went up by 2 miles on mixed driving. Good luck
 

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I think that the mechanic is trying to save his knuckles. Mine were really tight and my knuckles were cut up when I completed the process.
 

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spark plug

the worse thing could happen if your mechanic forced it , is he can only break the ceramic part. That was my experinced when I did mine. I broke a couple of my old spark plug, vacuum the hole and tried it again that time I sprayed some WD-40 set for a moment and tired again. DONE !
 

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kernith said:
I would be pissed if I had to pull a good head...
This is cracking me up!!!


Jim... How does the ceramic break? Is it because the socket crashes into it? Doesn't the metal nut transfer the torque directly to the metal threads? Maybe I need to look at a plug again.

I'm going to change mine soon, but I am stuck with a mental image of breaking off a plug and seeing parts of it drop into the cylinder. :eek: I think would just call a tow truck, go to the dealership and hand my ass across the cashier's window without saying a word.
 

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Discussion Starter #9
Well I spoke to the mechanic and he said he has twisited out a few threads on aluminum heads in the past, and he was not comfortable with the amount of pressure he was exerting. Since the engine runs good, he says to wait till 100K.I said fine and took the truck home. I plan to take it to the dealer and have the plugs changed. My manual says they should come out at 60K. I really don't balme the mechanic. He is a good Benz tech, but he runs a low overhead two man operation and only charges 60 bucks an hour. He works quickly and and only charges for his real time. This is the first time I was let down on a repair. I would have been more let down if I had to pull one of the heads...

We shall see what the dealer wants to do this.... guesses? My guess is 400.00 bucks.

Ken
 

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kernith said:
We shall see what the dealer wants to do this.... guesses? My guess is 400.00 bucks.

Ken
To change the spark plugs will be around ~$1000 for the V8 (including $17 x 16 spark plugs). It still may be worth it to feel secure knowing that if MB does screw up the head, they will repair it (hopefully). I'm going to try the WD-40 before I take mine out.
 

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Bogie said:
To change the spark plugs will be around ~$1000 for the V8 (including $17 x 16 spark plugs). It still may be worth it to feel secure knowing that if MB does screw up the head, they will repair it (hopefully). I'm going to try the WD-40 before I take mine out.
Bogie,
WD40 helps a LOT. Ceramic portion of the plug breaks off when you try to get the metal boot off and not by socket hitting it. I changed mine last weekend and it did happen. Also Bosch Platinum2 plugs were $3.99 at Napa. I am getting 2 miles more per gallon and engine runs smoothly. Good luck.
 

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Thanks SanMan. Good to know.

Does the ceramic part fall through the hole? or is there any danger of anything nasty happening?
 

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Bogie said:
To change the spark plugs will be around ~$1000 for the V8 (including $17 x 16 spark plugs). It still may be worth it to feel secure knowing that if MB does screw up the head, they will repair it (hopefully). I'm going to try the WD-40 before I take mine out.
In my Air Force career I worked on the big 28 cylinder Pratt& Whitney aircraft engines. I can honestly say I've changed thousands of spark plugs from aluminum cylinders (2 plugs per cylinder). The trick that never failed was CO2 from a fire bottle. I don't know if MB used steel heli-coils in their heads or not, but that is the fix if you happen to strip one out. I have drilled out, tapped and installed heli-coils in aluminum chevy heads with the head on the engine. Just vacumn out the cylinder. Drill with the piston at TDC. The other option would be dry ice packed around the plug. I can't believe MB would install the original plugs without some kind of anti-seize, so they're probably just tight and need more pull!
 

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Bogie said:
Thanks SanMan. Good to know.

Does the ceramic part fall through the hole? or is there any danger of anything nasty happening?
The ceramic part, in my case was stuck in the boot itself. I used shop vac to suck up any dust before taking the metal part out. No major issues. WD40 and mechanix gloves help a LOT. On the driver side use a 1.5 inch extention on top of 3 inch, then you can unscrew the plugs without hitting the heat shield.
 

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Discussion Starter #15
Bogie said:
To change the spark plugs will be around ~$1000 for the V8 (including $17 x 16 spark plugs). It still may be worth it to feel secure knowing that if MB does screw up the head, they will repair it (hopefully). I'm going to try the WD-40 before I take mine out.

OUCH! Well it is only a 6 cylinder so it should be much cheaper! :D

Ya know the MB service departments give the brand a little tarnish...

Ken
 

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ditto on San man

vacuum and WD-40 and a pair of gloves. the ceramic breaks when taking off the metal boot using 17mm wrench. DIY was fun and save money.
 

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Discussion Starter #17
JimB said:
vacuum and WD-40 and a pair of gloves. the ceramic breaks when taking off the metal boot using 17mm wrench. DIY was fun and save money.

I am getting tempted! I hate to scratch up my hands though. I am a dentist and I wear latex gloves all day. Scratches get infected during the time it takes to heal them. The glove powder gets rubbed into the wounds. And I never learned to work on cars without nicking up my hands!

Ken
 

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Give it a shot doc, invest in good leather gloves and you will be ok
 

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Discussion Starter #19
Panzer Man said:
In my Air Force career I worked on the big 28 cylinder Pratt& Whitney aircraft engines. I can honestly say I've changed thousands of spark plugs from aluminum cylinders (2 plugs per cylinder). The trick that never failed was CO2 from a fire bottle. I don't know if MB used steel heli-coils in their heads or not, but that is the fix if you happen to strip one out. I have drilled out, tapped and installed heli-coils in aluminum chevy heads with the head on the engine. Just vacumn out the cylinder. Drill with the piston at TDC. The other option would be dry ice packed around the plug. I can't believe MB would install the original plugs without some kind of anti-seize, so they're probably just tight and need more pull!

This is excellent stuff. Thanks!!

Ken
 

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Discussion Starter #20
I let the dealer do the plugs. They charged 365.75 labor and 111.00 for parts.

Not bad really. They programmed a new key for free, but then hit me for a 100.00 to turn on the front fog lights. I had found the harness and placed bulbs in the empty spots in the main head light unit. I thought this was excessive. I also needed a front plastic license plate mount which they ripped me for a 100.00. It seems MB is just always going to try to make a killing on parts. It tarnishes the brand.

Ken
 
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